Improvement in vulcanizing caoutchouc



UNITED STATES PATENT OFFICE,

OSCAR FALKE, OF COLLEGE POINT, NEW YORK, AND A. C. RICHARD, OF NEWTON,CONNECTICUT.

IMPROVEMENT IN VULCANIZING CAOUTCHOUC.

Specification forming part of Letters Patent No. 30,807, dated December4, 1860.

To all whom it may concern:

Be it known that we, ()soan FALKE, of College Point,in the county ofQueens and State of New York, and A. O. RICHARD, of Newton, Fairfieldcounty, Connecticut, have invented a new and useful Improvement inVulcanizing India-Rubber and Other Gums; and we do hereby declare thatthe following is a full and exact description thereof.

It is well known that india-Iubber goods are often defective from theimperfect mode of vulcanization. Sometimes the efflorescence of thesulphur is very objectionable, especially with goods treated with freesulphur and steam heat. Goods apparently excellent at first frequentlydeteriorate after a time. Owing to the different defects observed fromtime to time in such goods, manufacturers of indiarubber fabrics havebeen induced to institute numerous experiments in order to improve theprocesses of manufacture.

After trying many experiments, we believe we have made a new andvaluable improvement in vulcanizing caoutchouc, gutta-percha, and othervulcanizable gums.

Our invention consists in an improved process of vulcanizing caoutchouc,gutta-percha, and other vulcanizable gums by treating the same withsulphite of soda and sulphuret of antimony, accompanied by heat.

In order to vulcanize caoutchouc or indiarubber according to ourimproved process, we prefer to take about six parts of india-rubber andadd to this two parts of the sulphuret of antimony and one-half part ofthe sulphite of soda. Then'mix these ingredients and combine them bypassing the compound through heated rollers, such as are generally usedby manufacturers of india-rubber.- We also add various well-knowningredients to increasethe bulk or change the color as desired but theseare not essential to the success of our invention or improvement.

After the ingredients are intimately mixed with the india-rubber bygrinding, we roll the compound into sheets or spread it upon cloth orcut it into any desired form, and then subject it to the curing process,as follows: We

inclose the fabrics or compound in an iron vessel or heater, and raisethe heat immediately to 280 Fahrenheit and maintain that temperature onehour. Then we let the temperature fall to 275 Fahrenheit and sustainthat heat one hour. At the end of the second hour we reduce thetemperature to 270 Fahrenheit, and thus continue to cool down fivedegrees each hour until the rubber is complete- 1y cured.

The time required for curing the rubber depends upon the quality desiredin the fabric or article under treatment. To obtain a tough, strongarticle, the heat should be longer continued; and to obtain a veryelastic article, we continue theheat a shorter time. As a rule, wecontinue the heat not less than three hours and not more than tenhours,according to the effects desired to be produced, which effects arewell known to persons well acquainted with curing india-rubber.

Substantially the above-described mode of treatment is appliable togutta-percha and other vulcanizable gums. The proportions of theingredients and the amount of heat and other steps of the process may besomewhat varied without departing from our invention.

We do not claim the use of free sulphur or the compounds of lead, ofzinc, or of other substances heretofore employed in vulcanizingindia-rubber, gutta-percha, and other gums, but confine our claim to theuse of the abovedescribed ingredients or compounds of antimony and soda,when used in the manner and with the results above described.

Having thus fully described our invention, what we claim, and desire'tosecure by Letters Patent of the United States, is-

The use of the combination of the sulphuret of antimony and sulphite ofsoda, for thepurpose of vulcauizing caoutchouc, gutta-percha, and othervulcanizable gums, substantially in the manner above described.

OSCAR FALKE. ALBERT C. RICHARD.

Witnesses:

E. SIMON, F. F. SIMON.

